Impact of multiple cesarean deliveries on maternal morbidity: a systematic review

OBJECTIVE: The purpose of this study was to determine the impact of increasing numbers of cesarean deliveries on maternal morbidity. This study was performed for the 2010 National Institutes of Health Consensus Development Conference on Vaginal Birth After Cesarean: New Insights. STUDY DESIGN: We conducted a systematic review and metaanalysis of observational studies. RESULTS: Twenty-one studies (2,282,922 deliveries) were included. The rate of hysterectomy, blood transfusions, adhesions, and surgical injury all increased with increasing number of cesarean deliveries. The incidence of placenta previa increased from 10/1000 deliveries with 1 previous cesarean delivery to 28/1000 with >= 3 cesarean deliveries. Compared with women with previa and no previous cesarean delivery, women with previa and >= 3 cesarean deliveries had a statistically significant increased risk of accreta (3.3-4% vs 50-67%), hysterectomy (0.7-4% vs 50-67%), and composite maternal morbidity (15% vs 83%; odds ratio, 33.6; 95% confidence interval, 14.6-77.4). CONCLUSION: Serious maternal morbidity progressively increased as the number of previous cesarean deliveries increased.